Telecommunications systems and services today are in an era of rapid evolution aimed at providing alternatives to the wired public switched telephone network (PSTN). Most of the proposed alternatives to the conventional subscriber PSTN provide an added degree of mobility to telephone usage. Some of the presently existing options include:
1. So-called cordless telephones for use in and around the residence or workplace for both call origination and call reception.
2. Cellular telephones which were initially provided in automobiles over large areas but were generally limited to low traffic per unit area. Cellular telephones provide two-way but predominantly subscriber originated communications.
3. Conventional pay phones which provide islands of public access to the PSTN. Pay phones provide one-way calling for practical purposes.
4. Paging is a widely available service which serves an area as large as necessary. Generally speaking the communication is one-way to the subscriber customarily signals the subscriber to go to a telephone.
In addition to the foregoing existing services the objectives of enhanced mobility and multi-service terminals are now being addressed by two proposed new services, namely, telepoint and Personal Communications Networks (PCNs).
Telepoint in essence comprises an extension of the cordless telephone. The first generation of such service provides primarily call initiation and not complete two-way service. The telepoint subscriber is provided with a cordless handset which may be used within a predetermined range (presently about 100 yards) from a phone point which may constitute a home, office or public pay telephone. Phone point base stations can be sited in both indoor and outdoor public locations such as airports, railway stations, shopping centers, highways, etc., to allow authorized users to make telephone calls.
In use of such telepoint service the caller turns his/her handset on anywhere within the predetermined distance from a base station and presses the key sequence to access the base station. The handset then establishes a radio link with the base station. The handset also transmits to the base station stored authorization details or data. The base station in turn checks the authorization data and may prompt the user to manually enter a Personal Identification Number (PIN), if required. The base station checks that the PIN algorithmically matches the authorization data and that the authorization data is not on a locally held reject list. The caller is then prompted to dial the number he/she requires. The base station analyzes the dialed digits and decides if the call requires more detailed central authentication. If the caller is not authorized, as where the handset was stolen, the handset may be disabled by the base station so that it cannot be used again. If the call is authorized, the base station sets up the call via the PSTN.
The base station notes the time and date when the called subscriber answers and monitors the duration of the call. When the calling subscriber terminates the call the base station stores the call data such as the authorization details, date and time of call, call duration and dialed digits, etc., for later transmission to the central system for billing. A regional controller responsible to phone point management maintains a continuous surveillance on the system via the PSTN. Calls can either be billed directly to customers from the administration center or forwarded to the relevant network operator or program for billing.
A second proposed service, which is generally referred to as a Personal Communications Network (PCN), is a personal, totally portable, wireless communications network. PCN features a light weight, wallet sized cordless telephone connected to other telephones on and off the wireless network via a honeycomb of radio based microcells supported by an intelligent network, together with state of the art modulation techniques. PCN is intended to offer advanced voice and data communications totally independent of, or in tandem with, the PSTN. This new service is proposed to operate within a portion of the spectrum in the 1.7 to 2.3 GHz range. PCN is a generation beyond mobile phones as known in the cellular service today. Because it will use microcells which will greatly expand frequency use and reuse PCN will be available to greater masses of users. Because of its intelligent network it is proposed that personalized "smart cards" be provided to offer advanced service features such as highly selective call ringing and rejection, virtual private networks and ISDN features.
Such PCN service is not presently available in the United States but has been provided on a limited basis in the United Kingdom. However, PCN's spectrum demands and ubiquity require a large allocation of dedicated spectrum which is likely to entail delay in wide scale introduction of such a service in the United States.
While the movement toward these new and advanced services is in progress there remains a pressing need for immediate enhancement of the services which the PSTN is capable of providing. It is a purpose of the present invention to supply that need both on an immediate and long term basis.